The project is aimed at improving the estimate of the number of VH and VL genes normally required for antibody synthesis by determining how significant a reduction in the number of these genes is achieved by assembling different antibody molecules from one heavy or light chain sequence and multiple forms of the complementary chain sequence. Extensive structural studies will be carried out on anti-p-azobenzoate antibodies of limited heterogeneity to estimate the number of different heavy and light chain sequences in the same antibody preparation. In other experiments attempts will be made to isolate different IgG antibodies having a common heavy or light chain and to study their specificities.